Surgical treatment of the vitreous body of the eye by vitreous body surgery is indicated for example in the event of loss of vitreous body during cataract operations, in the event of injuries to the front part of the eye, in paediatric surgery, in retinopathy or in complicated retinal detachments. Different methods are known for this.
The method of choice is Pars Plana Vitrectomy (PPV) which was introduced at the beginning of the 1970s. It is a closed, intraocular microsurgical process in which access to the vitreous space is obtained through the Pars Plana. PPV allows the seamless insertion and removal of surgical instruments through the conjunctiva which is otherwise closed. As a rule, in PPV, a total of 2-3 incisions are required, the diameter of the instruments inserted being 1.0 mm (19 gauge) or 0.9 mm (20 gauge). As a rule, one infusion channel and two working channels are made, enabling the diameter of the individual incisions to be reduced by comparison with a shared access. The effective trauma when a number of small incisions are made is certainly less than when there is one large incision, but the diameter of the individual incisions and the number of incisions should be kept as small as possible.
The standard that has proved successful for illuminating the interior of the eye, as required during PPV, is an endoprobe held in the surgeon's non-dominant hand and introduced into the eye, this endoprobe being connected to an optical fibre. With his dominant hand the surgeon holds the surgical instruments which are then used one-handed to make interventions on the vitreous body and retina. For simpler surgical procedures such as the elimination of a vitreous bleed and the removal of pre-macular membranes, one-handed guidance of the instruments is often practicable. However, for more complex operations inside the eye, two-handed operation is desirable.
In the so-called multiportal illumination system (MIS) developed by Koch et al. (1992) (cf. Augustin, “Augenheilkunde”, 3rd Edition, Springer-Verlag Berlin, Heidelberg, 2007), active bimanual vitreous surgery with full wide-angle observation is made possible by the introduction of instruments with a diameter of less than 19 gauge (less than 1.0 mm) into the eye through illuminated cannulas. As a result, no additional illumination, e.g. by hand-held optical fibres, is required.
An alternative method of bimanual vitreous surgery was proposed by Schmidt et al. (“Bimanuelle Membranextraktion bei schwerer proliferativer diabetischer Vitreoretinopathie mit permanenter Endoillumination”, Spektrum Augenheilkd. 2003, 17, 177-180). In this, a fourth incision is made through which a light probe is introduced.
For wide angle observation during vitreous surgery, lenses are generally arranged between the operating microscope and the patient's cornea. Apart from so-called corneal contact lenses, the positioning of which is carried out by assistants or by using a retaining ring placed directly on the cornea, wide-angle attachments for operating microscopes are also used.
In order to achieve a sufficient wide-angle view, as a rule aspherical lenses are used in both cases, which produce a reversed, upside down image. The image reversal is acceptable during diagnosis. However, during eye operations the reversal of the image leads to coordination problems, even with experienced surgeons, while the reversed stereopsis is an additional aggravating factor.
Therefore, for the fields of use described, the use of devices for reversing and righting images is known and is described for example in DE 36 15 842 A1, DE 3826069 A1, DE 200 21 955 U1 and WO 91/15150 A1. However, the additional components should not appreciably increase the height of the microscope as the surgeon has to carry out the operation and look through the microscope at the same time. The distance between the eyepiece of the microscope and the patient's eye thus cannot be increased at will.
Moreover, the device for reversing and righting the image should also be capable of being pivoted into the optical path of the microscope as quickly as possible so that it is possible to operate both in the front section of the eye and at the back of the eye without having to change the microscope. It is therefore expedient to use different prism systems (generally with Porro prisms) as disclosed in the above-mentioned DE 200 21 955 U1, which are arranged at the microscope end of the wide-angle lens used.
WO 91/15150 discloses a prism arrangement in which a prism is arranged to be movable in order to lengthen or shorten the observation beam path. This makes it possible to maintain the focus of the microscope even with non-emmetropic eyes when the wide-angle device with its associated prism arrangement for righting the image is pivoted outwards or inwards.
However, the systems proposed still require the insertion of an optical fibre into the eye. As already mentioned, however, it is desirable to reduce such incisions as much as possible.
Furthermore, DE 10 2009 058 792 B3, which was a prior application with respect to the filing date or priority date of the present application in Germany but was published later, relates to an optical observation device for observing an eye. This optical observation device comprises a microscope for observing the front section of the eye and a visualising system that can be pivoted in front of the microscope for observing the retina of the eye. The microscope and the visualising device are used exclusively, i.e. when viewing the front part of the eye the visualising device is pivoted out of the beam path of the microscope, whereas when observing the retina of the eye the attachment module is pivoted in, the observation of the retina then taking place by means of the visualising device which has at least one digital camera, the data from which are supplied to a reflecting or superimposing device of the microscope. The image of the retina can be made visible through the eyepiece of the microscope by means of a display of the reflecting device and corresponding optics and beam splitters. The solution proposed here is complicated as the visualising device itself constitutes a kind of microscope and a reflecting device has to be provided to render the data of the visualising device visible on the microscope. Moreover, the proposed visualising device is not a wide-angle device in the sense of the present application.
From DE 10 2006 038 911 A1, an ophthalmoscopic attachment module is known for attachment to an operating microscope for observing the back of a patient's eye. The background to the solution proposed in this specification is the avoidance of disruptive light reflections emanating from the illuminating light, reflected on the ophthalmoscopic magnifying lens of the attachment module. Therefore, this publication proposes various solutions for guiding light from the microscope illumination past the ophthalmoscopic magnifying lens towards and into the patient's eye that is to be examined. In another embodiment the attachment module has its own light source with illuminating optics. Illuminating light produced there is guided via reflective surfaces past the ophthalmoscopic magnifying lens into the patient's eye. The attachment module proposed therein is, once again, not a wide-angle device in the sense of the present application.
The objective of the present invention is therefore to provide a possible illumination which allows bimanual ophthalmological operations, particularly vitrectomies, without the need for the insertion of a cannula with optical fibre into the patient's eye, and by means of which at least the object field perceived by the observer is fully illuminated at the same time.